Adult patients cart be instructed to remain quiescent while they are connected to intravenous, catheters, endotracheal tubes, and various monitoring devices. Infant victims of congenital heart disease and animal patients, on the other hand, cannot be expected to cooperate in such a situation, even if restrained, without continuous anesthesia or sedation. This anesthetized or sedated state cannot be continued indefinitely without producing a life-threatening situation of its own. Hence, it would be advantageous to be able to replace or supplement the heart's pumping action with an implant or multiple implants, at least until a suitable donor organ is obtained.
Many artificial hearts and heart booster devices ("ventricular assists") are known, but they nearly all depend upon some direct connection to the outside of the body through invasive surgical appliances. They are, however, primarily aimed at helping the patient to survive until a genetically compatible donor heart can be obtained. Research continues on implantable pumps or "ventricular assists," particularly for use whenever complete heart replacement is not indicated.
The evolution of such implantable devices has been paced by the state of the art technology. As microelectronic devices of extremely small size and reliability have been developed for communication, instrumentation, calculation and control, very complex miniature devices have been made possible. Rechargeable battery technology also has progressed considerably during recent years.
Accordingly, it is an object of the present invention to provide a fully implantable electric pump for assisting blood flow in a patient in need thereof.
Another object is to provide such a pump which is surgically insertable into, or parallel with, a ventricular outflow artery and causes at least some of the blood ejected by a ventricle to be forced through a central axial flow path of the pump.
A further object is to provide such a pump wherein the rotor is relatively freely rotatable by the blood flowing in the central axial flow path in the absence of any magnetic field within the stator--i.e., in case of an electrical failure in the pump.
Another object of the present invention is to provide such a pump which is relatively simple and inexpensive to manufacture, use and maintain.